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Date: | Tue, 27 Oct 2009 19:22:30 +0100 |
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There is always the definite possibility of a bug in ECJ: for example,
I just routed out a long-standing one in Lawnmower recently (check
CVS). But another reason may be that Koza-I and Koza-II'ss results
have proven historically difficult to reproduce. There are a number
of reasons for this, but here are two: the random number generator
used in Koza-I and Koza-II was troublingly non-random; and certain
variables are not as you'd expect in print. For example, though Koza-
I says 400 timesteps for Artificial Ant, in fact it's believed he used
600. So much subsequenty work used 400 timesteps as a result that
that's the default for both ECJ and lil-gp. You an change it to 600
and see what's up. There are other explanations for differences which
have been offered which I don't want to get into here.
So: if we can nail down a bug, I'd love to find out. But be prepared
for the probability that it's Koza-I and not ECJ. One way to check for
the possibility of an ECJ bug in certain problems is to run lil-gp and
see which one it more or less agrees with. Let me know what you get.
Sean
On Oct 27, 2009, at 5:37 PM, David F. Barrero wrote:
> Dear all,
>
> I am trying to reproduce Koza's performance curves for some typical GP
> problems implemented in ECJ, but I had a limited success. Some
> problems
> such as simple regression have similar performance curves compared
> with
> the ones shown in Koza I, while others (for instance, Santa Fe trail
> or
> even 5 parity with ADFs) yields very different curves.
>
> In theory, should ECJ examples generate the same performance curves
> than
> those shown in Koza I/II?.
>
>
> Thanks in advance,
>
> David
>
>
>
>
> --
> David F. Barrero
> Departamento de Automática
> Universidad de Alcalá
>
> Tlf: (34) 91-885-69-20
> Web : http://atc1.aut.uah.es/~david/
> Jabber/GTalk: [log in to unmask]
> Skype: dfbarrero
>
> Escuela Politécnica
> Departamento de Automática
> Despacho E-236
> Ctra. Madrid-Barcelona km 31,600
> 28871 Alcalá de Henares. Madrid
> --
>
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